What's a Hamilton-made plane doing in North Korea?

It's potentially a public relations nightmare - one of your planes turning up in a North Korean air show, painted with the totalitarian state's national colours.

But New Zealand-based Pacific Aerospace says it's confident no United Nations sanctions have been broken, after a 10-seater made at its base in Hamilton starred in the Wonsan International Friendship Air Festival last week.

Tech magazine Popular Mechanics spotted the PAC P-750 XSTOL amongst Russian-made Sukhoi and Mikoyan jets and a fleet of US-made helicopters North Korea illegally obtained in the 1980s.

"We're trying to get some answers about what that all means," chief executive Damian Camp told Newshub on Monday.

The US$2 million plane was sold to Chinese company Free Sky several months ago. Mr Camp says he's sure its appearance in Wonsan is "quite innocent", but wants to make it clear his company has no dealings with the isolated Communist nation.

"We can't restrict people from flying where they want to fly. No doubt they're trying to build some profile about their company… in the local market."

The PAC P-750 XSTOL in action (YouTube)

While the PAC P-750 XSTOL has a top speed of 315km/h, answers might be a bit slower coming out of Free Sky because China's currently in its Golden Week holiday.

"As long as they're doing everything right and not cutting across any restrictions that are placed on New Zealand companies like us, then we're okay with that," says Mr Camp. "But clearly we want to get to the bottom of it."

The plane has no military capabilities so would probably be of little interest to Kim Jong-un's regime, says Mr Camp.

Planes are just one thing UN members aren't allowed to trade into North Korea, with sanctions against the country strengthening after it tested a nuclear device earlier in the year. Other contraband includes rare earth minerals, aviation fuel, weapons, luxury goods like snowmobiles and pocket watches, yachts and racing cars.

About two-thirds of North Korea's external trade is with China. Only a quarter is with its official enemy to the south.